Liquid detergent composition



cohol.

added to an already complicated formula, these suds builders mayrequire, in certain formulations, a partic- United States Patent Ofice3,085,982 Patented Apr. 16, 1963 3,085,982 LIQUID DETERGENT COMPOSITIONDavid C. Steer and Norman R. Smith, Cincinnati, Ohio,

assiguors to The Procter & Gamble Company, Cincinnati, Ohio, acorporation of Ohio No Drawing. Filed Apr. 22, 1959, Ser. No. 808,022 8Claims. (Cl. 252-437) This invention relates to liquid detergents ofmediumduty and heavy-duty, sudsing type. More particularly, it relatesto improved liquid detergents which contain a tertiary amine oxidesurface active agent.

In recent years built liquid detergents have been gaining favor forwashing soiled clothing, for washing dishes and for other purposesrequiring an effective detergent. A built detergent is one whichcontains, in addition to the surface active agent, a soluble saltcapable of sequestering calcium and magnesium ions of hard water andalso capable of increasing the level of detergent effectiveness of thesurface active agent. Built liquid detergents have, to some extent,replaced granular built detergents for various reasons. These reasonsinclude: complete freedom from dustiness, compact package, conveniencein pouring and measuring, and simplification of manufacture.

The problems which have to be overcome in formulating built detergentsin clear homogeneous liquid form are mainly the problems ofincorporating sufficient surface active agent and builder into the samesolution. In current practice an anionic sulfated or sulfonated compoundis ordinarily used as surface active agent, and potassium pyrophosphateis used as builder. Various surface active agents, hydrotropes andsolvents are employed to increase their compatibility. The fact that thebuilder may corrode non-ferrous metals such as aluminum, may, dependingon the use for which the product is intended, lead to the inclusion ofsodium silicate as a corrosion inhibitor. Its presence requires thatspecial provisions be made to keep the ingredients compatible.Limitations on the pH of the formulation or the presence of agentsdesigned to achieve compatibility is usually required.

In U.S. Patent 2,859,182 a combination of alkali metal aryl sulfonateand at least one alkylolamide is disclosed for making certain detergentcompositions homogeneous. In these compositions the pH must be adjustedto about 11.4 or above to keep silicate in solution.

Different agents for solving the problem of making detergent, builderand silicate compatible, which are disclosed in US. Patents 2,877,185and 2,877,186, are: a solubilizing agent, for example triamylphosphateor potassium benzene sulfonate; and an assistant solubilizer," forexample ethyl alcohol or diethyleneglycol monobutyl ether; and aparticular detergent, alkyl glyceryl ether sulfonate. The alkyl glycerylether sulfonate and the solubilizing agent are used together, and theassistant solubilizer is preferably included.

Liquid detergents generally contain one or more agents, called sudsbuilders, to increase their sudsing. Typical suds builders are coconutethanolamide and lauryl al- In addition to being one more ingredient tobe ular perfume to cover their odor. Amide-type suds builders, unlesspurified, are often undesirably highly colored for use in liquidproducts. They are not considered to serve the cleaning function of adetergent.

An object of this invention is to provide a homogeneous built liquiddetergent of improved sudsing characteristics and good detergenteffectiveness.

A further object of this invention is to eliminate suds builders from ahigh sudsing liquid detergent formulation.

An additional object of this invention is to eliminate the need forsolvent and/ or special surface active agents (alkylolamide oralkylglyceryl ether sulfonate) in a homogeneous built liquid detergent;the object of an aspect of the invention is to do so when silicate ispresent.

These and other objects are accomplished by a detergent formulationcontaining: (I) from about 3% to about 10% of an aliphatic tertiaryamine oxide; (2) from about 3% to about 15% of a non-soap syntheticdetergent of the sulfated or sulfonated type; (.3) from about 3% toabout 10% of a soluble hydrotrope; and (4) from about 10% to about 30%of a soluble pyrophosphate salt. These ingredients are dissolved in anaqueous vehicle. When the use of the formulation makes a corrosioninhibitor desirable, from about 3.5% to about 6% of alkali metalsilicate solids are dissolved in the same solution.

In the following more complete disclosure of the invention, percentagesrefer to weight percent of the total formula unless otherwise indicated.It will be appreciated that in an aqueous system it is for the most partimmaterial by which ionic salts a particular ion is introduced; for inthe aqueous product there will be substantially complete and continuousexchange of ions.

Amine oxides are compounds of the general formula R R R N- O. The arrowis a conventional representation of a semipolar bond. They are generallyprepared by the direct oxidation of the appropriate tertiary amine. WhenR is a much longer chain than R and R amine oxides have surfaceactivity. For the purpose of this invention R is an alkyl radical offrom about 10 to about 16 carbon atoms. Desirable surface activeproperties are lost if R is substantially less than 10 carbon atoms, andsolubility in the present formulation is too low if R is greater than 16carbon atoms. R and R are each selected from the group consisting ofmethyl and ethyl radicals. Preferably R is a dodecyl radical or amixture of dodecyl with de-cyl, tetradecyl and hexadecyl radicals, suchthat at least 50% of the radicals are dodecyl radicals. A convenientsource of a preferred mixture is the middle cut of coconut fatty alcoholwhich has the approximate chain length composition: 2%C 66%C 23%C, and9%C R and R are preferably methyl radicals. The amine oxide is used atfrom about 3% to about 10% of the total formula. Too little amine oxideadversely affects the performance of the formulations and too much amineoxide interferes with achieving builder and detergent in sufficientamount in a homogeneous liquid.

Soluble pyrophosphate salts are suitable builders in this invention.They complex the calcium and magnesium ions of hard water; and, when thecalcium ions of hard Water are present in excess, have an additionalwater softening effect by precipitating calcium pyrophosphate. They alsoserve to increase the level of detergency obtainable with syntheticsurface active agents. Potassium, sodium, ethanolammonium,diethanolammonium, and triethanolammonium are suitable salts of thepyrophosphate anion in the practice of this invention; potassiumpyrophosphate is especially preferred. The soluble salt of pyrophosphateis employed at a level of from about 10% to about 30%.

The pyrophosphate salts, like other sequestering agents, are corrosivetowards aluminum. If the detergent solution is to contact this metal forprolonged periods of time, especially at elevated temperatures, acorrosion inhibitor should be desirably included. In a product designedfor hand laundry of fine fabrics, it is unnecessary. Soluble silicatesare highly effective inhibitors and can be added to the formulas of thisinvention without difficulty at levels of from about 3.5% to about 6%.Potassium, or preferably sodium silicates haviug a weight ratio ofSlog/M20 of from about 1.0 to about 2. 6 and preferably from about 1.6to about 2.6 can be used. M in this ratio refers to sodium or potassium.Less than about 3.5% sodium silicate solids, although useable in thepresent compositions, does not provide protection against corrosion attypical use conditions, and more than about 6% sodium silicate solids isdifficult to incorporate into a homogeneous liquid.

Suitable hydrotropes to increase the compatibility of the ingredients ofthe formulations of this invention are the aryl sulfonates disclosed inthe hercinbefore cited patents. More specifically they are soluble saltsof the hydrotrope anions. Preferred hydrotrope anions are benzenesulfonate, xylene sulfonate and toluene sulfonate. They are used as thesoluble salts such as: ethanolammonium, diethanolammonium, andtriethanolammonium and especially as the alkali metal, potassium, orsodium, salts. Sodium or potassium toluene sulfonate is especiallypreferred. The hydrotrope salt is added at levels of from about 3% toabout 10%. Levels of from about 4% to about 6% are preferred. The upperlimit of about 10% is set by increasing dilution of the product by aningredient substantially inert so far as sudsing and detergency areconcerned. The lower limit is the amount required to achieve ahomogeneous solution. It will be appreciated that it is necessary thatthe formulations of this invention should be liquid at somewhat higherand at somewhat lower tem peratures than usual room temperature. Theamount of hydrotrope salt used is preferably the minimum amount whichwill hold the ingredients in solution at the temperature to which it isdesired that the formula can be cooled without phase separation.

Amine oxide is an effective detergent; however, in order to achieve theobjects of this invention, a supplemental non-soap anionic syntheticdetergent is added. From about 3% to about 15% anionic detergent isemployed. Preferred anionic detergents which can be included are: alkylbenzene sulfonate, alkyl ethylene oxide ether sulfate wherein there arefrom 1 to ethylene oxide residues per alkyl and the mixtures formed when1 to 5 ethylene oxides are reacted with one mole of alcohol, and alkylsulfate. These may be represented, respectively, as:

where x is an integer from 1 to 5, and R80 In these compounds the alkylchain (R) will contain from about 9 to about 16 carbon atoms andpreferably about 12 carbon atoms. Mixtures of alkyl radicals ofdifferent chain lengths are preferably used since they are soluble andreadily available from synthetic or natural sources, e.g., coconutalcohol and a mixture containing tri-, tetra-, and pentapolypropylenepolymers and averaging about 12 carbon atoms. These detergents are usedas soluble salts; specifically, they are used as sodium, potassium,ethanolammonium, diethanolammonium and triethanolammonium salts. Sodiumand triethanolamine salts are preferred. Other non-soap anionicsynthetic detergents, with alkyl radicals as specified above, can beusefully employed if they have the following characteristics: theirsalts, as specified above, are soluble to the extent of at least 3% inan aqueous solution of 3% dimethyldodecylamine oxide, 3% potassiumtoluene sulfonate and potassium pyrophosphate; and they are stableagainst hydrolysis in alkaline solution. An example is the potassiumsalt of the sulfated condensation product of four moles of ethyleneoxide with a mole of nonyl phenol.

The formulas of this invention, containing amine oxide, suds so well inthe laundry and dishpan that no suds builder is required. Among theanionics, the alkyl sulfate makes a particular contribution to sudsingin the formulas of this invention. Alkyl benzene sulfonate isparticularly favored for this purpose because in most circumstances itreduces the cost of the formula. A supplemental anionic detergent cantend to improve the mildness of the formulations, alkyl benzenesulfonate being particularly noteworthy in this respect. Thesupplemental anionic detergents also permit the achieving of higherlevels of active ingredients in a homogeneous liquid. Alkyl benzenesulfonate and alkyl sulfate are therefore especially preferred anionicdetergents. Preferred formulas of this invention include those in whichtwo anionic detergents are used in combination with the amine oxide. Forexample, C alkyl benzene sulfonate, coconut alkyl sulfate anddimethyldodecylarnine oxide in approximately equal quantities in adetergent combination which gives superior sudsing. good mildness to theskin and relatively low cost and is especially preferred in the practiceof this invention. Slight variations from equal quantities of the amineoxide and the anionic detergents permits fine adjustment of theproperties of the formulas. If more of one detergent is used, preferablyless of another is used. To maintain the homogeneous character of theproduct, the sum of anionic detergent and amine oxide is preferably keptin the range of from about 10% to about 25%.

The inorganic builder content is preferably raised as the totalsynthetic detergent content is lowered; so that the sum of builder anddetergent is kept from about 25% to about 40%. In this range ofcomposition the product has particularly good performance andhomogeneous character. As a rough generalization, when the totaldetcrgent is greater than the builder the product is of medium-duty typeand can be recommended for hand laundering of fine fabrics anddishwashing. When the detergent level is lowcr or equal to the builder,the product is of heavy-duty type especially adapted for laundry andgeneral purpose use. Silicate is particularly desirable in theheavy-duty product.

In a finished detergent formulation there will preferably be added inminor amounts materials which make the product more effective or moreattractive. The following are mentioned by way of example. A solublesodium carboxymethylcellulose may be added in amounts up to about 2% toinhibit soil redeposition. A tarnish inhibitor such as benzotriazole orethylenethiourea may be added in amounts up to about Fluorescers,perfume, and color, while not essential in the compositions of theinvention, may be added in amounts less than about 1%.

All the constituents of these liquid detergent formulations aredissolved in water with the possible exception of certain of the minornonessential ingredients which are at least finely and homogeneouslydispersed to give the effect of a onephase composition. A maximum waterlevel of about 70% is set by the need to get enough active ingredient inthe solution to hold the volume required per usage to an acceptablelevel. The minimum water level of about 45% is set by the requirement ofhaving sufiicient water to dissolve the ingredients.

The mole ratio of potassium (and any alkanolammonium ions) to sodium ismaintained above about 3:1 to maintain the one-phase nature of theproduct and preferably is maintained above about 3.511.

Example I The following compositions were prepared and examined. Allwere clear homogeneous pourable liquids at room temperature. Formulas Band C were cooled to lower temperatures and remained clear at 50 F.

Dimethyldodccyl amino oxide percent 4 5 7 5 8 6 Sodium polypropylenebenzene sulfonate (a mixture. of tri-, tetrm, and peutapropylenitaveraging about C12} percent" 4 ti 3 5 Sodium coconut sulfate. .do 4 2 34 4 8 Potassiutntoluencsulfunate do. 6 7 G t, 6 (Ilotassiumpyrophosphate lo. 15 18 18 ltt 18 Sodium silicate solids S5102:

' r at," as as} as as as is ,do 0.1) (1.15 Water do t l l?) (IK/Nu,approx 1nole rutio lo 4.1 4.2 l o i 5.0 d J 1 Coconut refers to thealkyls of lllltltllt? cut coconut ult-ohul containing about 292-010.[itilk-On, filmy-Cu ul1tl9;T;,.-C s.

2 Balance.

An additional composition, G, was prepared as a duplicate of F exceptthe 8% sodium coconut sulfate was replaced by 6% potassium salt of asulfated condensation product of one mole coconut 1 alcohol with 3 molesof 1 Coconut refers to the alkyls of middle out coconut alcoholcontaining about 2%Cio, 66%Ci2, 23%'C14. and 9%Cld. ethylene oxide. TheK/ Na mole ratio in this product was about 7.4.

Products A, C, D, and F proved to be superior in maintaining suds duringthe washing of soiled dishes to com- 10 mercially available built liquiddetergents tested under the same conditions. Products B and G proved tobe good dishwashing products, being about equal to available builtliquid products.

Products B and C were also employed in washing soiled clothes in atypical domestic washing machine. The suds in the first load was higherthan for commercial built liquid detergents tested under the sameconditions.

The sodium silicate can be omitted from these formulas withoutsubstantially affecting appearance or performance except for theircorrosiveness to non-ferrous metals. Dodecyl radicals and coconutradicals are substantially equivalent, that is one can be substitutedfor the other in the ingredients of this example with no substantialchange in appearance or performance of the product. Potassium benzenesulfonate or potassium xylene sulfonate can be used to replace potassiumtoluene sulfonate without losing the homogeneous nature of the productor adversely affecting its performance.

Example I] The following composition was prepared. It was a clearhomogeneous pourable liquid at room temperature. It remained clear at 30F.

Percent Dimethyldodecylamine oxide 6 Triethanolamine salt ofpolypropylene benzene sulfonate (a mixture of tri-, tetra-, andpentapropylene averaging about C 6 Potassium pyrophosphate 25 Potassiumtoluene sulfonate 8.5 Sodium silicate solids, Si0 to Na O is 1.6 5 WaterBalance K-l-triethanolammonium/Na, approx. mole ratio 5.5

The suds during washing soiled dishes obtained from this product weremore stable than suds obtained from commercially available built liquiddetergents. This product showed good sudsing and cleaningcharacteristics in washing soiled clothing.

Example 111 The following compositions were prepared. They were clearhomogeneous pourable liquids at room temperature. After freezing at 40F. they again became clear and homogeneous on being warmed to roomtemperature.

I A l B Dirnethyleoconut I amine oxide 5.0 6.0 Sodium coconut 1 ethyleneoxide ether suit-ate (average of 3 ethylene oxide residues per molecule)8. 5 10.0 Sodium coconut I alkyl sulfate 2. 5 Sodium polypropylenebenzene sullonate (a mixture oitri-, tetra, and pentapropyleue averagingabout C12) 4.0 4.0 Potassium pyrophosphate 12 12 Potassium toluenesuli'onate 5 5 Color 0.0013 0 0013 Bonzotriazole 0. 02 (I. 02 WaterBalance Balance K/Na, approx. mole re 4. 2 4. S

i (oconut refers to the alkyls of middle out coconut alcohol containingabout 2G1t, 6651-0 2, 237 -014, and9%C for the purposes for whichmedium-built liquid products are intended.

In these compositions, methylethylcoconutamine oxide ordiethylcoconutamine oxide can be substituted for dimethylcoconutamineoxide without substantially adversely affecting the physicalcharacteristics or performance of the compositions.

What is claimed is:

1. A substantially clear, high-sudsing, concentrated liquid detergentcomposition consisting essentially of:

(a) from about 3% to about 10% of an aliphatic tertiary amine oxidehaving the general formula R R R N- 0, where R; is an alkyl radicalcontaining from about 10 to about 16 carbon atoms and R and R are eachselected from the group consisting of methyl and ethyl radicals, atleast about 50% of said amine oxide having R containing 12 carbon atoms;

(b) from about 3% to about 15% of a non-soap detergent selected from thesalts of the group of detergent anions consisting of R R(OC H SO where xis an integer from 1 to 5 R being an alkyl radical containing about 9 toabout 16 carbon atoms, and mixtures thereof;

(0) from about 3% to about 10% of a salt of a hydrotrope anion selectedfrom the group consisting of toluene sulfonate, benzene sulfonate, andxylene sulfonate;

(d) from about 10% to about 30% of a salt of a pyrophosphate anion; andthe balance substantially (e) water; the cations of the salts of thegroup of detergent anions, of the salts of the hydrotrope anions, and ofthe salts of the said pyrophosphate anion being selected from the groupconsisting of potassium, sodium, ethanolammonium, diethanolammonium, andtriethanolammonium, and the mole ratio of the total of potassium and ofalkanolarnmonium cations to sodium cations being greater than about 3:1,said composition being substantially free from amide suds-builders.

2. The liquid detergent composition of claim 1 wherein in the tertiaryamine oxide R and R are each methyl radicals.

3. A substantially clear high sudsing concentrated liquid detergentcomposition consisting essentially of:

(a) from about 3% to about 10% of an aliphatic tertiary amine oxidehaving the general formula R R R N- O where R is an alkyl radicalcontaining from about 10 to about 16 carbon atoms and R and R are eachselected from the group consisting of methyl and ethyl radicals, atleast about 50% of said amine oxide having R containing 12 carbon atoms;

(b) from about 3% to about 15% of a non-soap detergent selected from thesalts of the group of detergent anions consisting of R80 R(OC H SO wherex is an integer from I to 5 R being an alkyl radical containing about 9to about 16 carbon atoms, and mixtures thereof;

(0) from about 3% to about 10% of a salt of a hydrotrope anion selectedfrom the group consisting of toluene sulfonate, benzene sulfonate, andxylene sulfonate;

(d) from about 3.5% to about 6% of silicate solids of the compositionSlOgIMgO their weight ratio being from about 1.6:1 to about 2.6:] andwherein the M of M 0 is selected from the group consisting of sodium andpotassium;

(e) from about 10% to about 30% of a salt of a pyrophosphate anion; andthe balance substantially (f) water; the cations of the salts of thesaid detergent anions, of the salts of the said hydrotrope anions, andof the salts of the said pyrophosphate anion being selected from thegroup consisting of potassium, sodium, ethanolammonium, andtriethanolammonium, the mole ratio of the total of potassium andalkanolammonium cations to sodium cations being greater than about 3:1,said composition being substantially free from amide suds-builders.

4. The liquid detergent composition of claim 3 wherein the amine oxide Rand R are each methyl radicals.

5. The liquid detergent of claim 3 wherein the detergent anion is Rbeing an alkyl radical containing from about 9 to about 16 carbon atoms.

6. The liquid detergent composition of claim 3 wherein the detergentanion is a mixture of R -s Os-and R s or R being an alkyl radicalcontaining from about 9 to about 16 carbon atoms.

7. The liquid detergent composition of claim 3 wherein the hydrotropeanion is toluene sulfonate.

8. A substantially clear high-sudsing liquid detergent compositionconsisting essentially of:

(a) from about 3% to about 10% of an aliphatic tertiary amine oxidehaving the general formula R R R N O where R is an alkyl radicalcontaining from about 10 to about 16 carbon atoms and R and R are eachmethyl radicals, at least about 50% of 8 said amine oxide having Rcontaining 12 carbon atoms;

(b) from about 3% to about 15% of a sodium salt of a non-soap detergentanion selected from the group consisting of R R(OC H SO where x is aninteger from 1 to 5 References Cited in the file of this patent UNITEDSTATES PATENTS 2,060,568 Graenacher et al Nov. 10, 1936 2,169,976Guenther et al Aug. 15, 1939 2,581,677 Machlis et al Jan. 8, 19522,877,186 Krumrei Mar. 10, 1959 FOREIGN PATENTS 437,566 Great BritainOct. 31, 1935 OTHER REFERENCES The Chemistry of Fatty Amines, 1948, pub.by Armour and Co., page 13.

1. A SUBSTANTIALLY CLEAR, HIGH-SUDSING, CONCENTRATED LIQUID DETERGENTCOMPOSITION CONSISTING ESSENTIALLY OF: (A) FROM ABOUT 3% TO ABOUT 10% OFAN ALIPHATIC TERTIARY AMINE OXIDE HAVING THE GENERAL FORMULA R1R2R3N$O,WHERE R1 IS AN ALKYL RADICAL CONTAINING FROM ABOUT 10 TO ABOUT 16 CARBONATOMS AND R2 AND R3 ARE EACH SELECTED FROM THE GROUP CONSISTING OFMETHYL AND ETHYL RADICALS, AT LEAST ABOUT 50% OF SAID AMINE OXIDE HAVINGR1 CONTAINING 12 CARBON ATOMS; (B) FROM ABOUT 3% TO ABOUT 15% OF ANON-SOAP DETERGENT SELECTED FROM THE SALTS OF THE GROUP OF DETERGENTANIONS CONSISTING OF RSO4-, R(OC2H4)XSO4-, WHERE X IS AN INTEGER FROM 1TO 5